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Providing End-to-End Network QoS via Overlay Networks and

Bandwidth On-demand

Mauricio ArangoSun Microsystems

October 2007

Mauricio.Arango@sun.com

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Internet’s QoS Problem – A result of the Dumb Network Approach • Based on End-to-end principle:

> Advocates minimal core network functions with emphasis on functions at the periphery

> Routing is part of core functions – tightly coupled with packet switching fabric, highly distributed

• Problem - Emphasis on minimal core functions left out key basic features: > Quality of Service (QoS)> Performance Monitoring > Accounting

• A solution - Add needed core functions, “Intelligence”, via Overlay Networks on top of current dumb core

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Internet’s QoS Problem – A business opportunity• Lack of assured QoS is a business problem

> “Throwing more bandwidth” solution approach isn’t cost-effective

• Rapid traffic growth, specially video, exacerbating problem

• Growing business sectors exploiting opportunity through overlay network approaches> Content Delivery Networks (CDN) - Managed QoS

services > Application Delivery and Wide-area Optimization

Controllers

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The QoS problem is a routing problem

• Internet’s routing > Doesn’t take into account network performance

conditions > Doesn’t take into account endpoint performance

conditions, such as data center problems • Overlay solution approach

> Why - Changing existing infrastructure is too complex and expensive

> How – hierarchical routing – adding higher-level routing layer that bases decisions on performance data

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Overlay Networks

• Compensate network weaknesses with computing power: e.g. caching, application-based routing

> An application of Butler Lampson’s principle: "All problems in computer science can be solved by another level of indirection"

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Overlay Architecture Patterns

• Interception Point – Network element on path of traffic flow, performs packet inspection. Minimally invasive:> Open control points – eg. DNS> Interconnection points – eg. peering points

• Decision Point – Applies rules and executes triggered actions – local or remote

Interception & local decision points

Backbone ISP

Backbone ISP

Backbone ISP Access

ISP

Backbone ISP

Backbone ISP

CustomerNetwork

Internet Backbone

Control & Management OverlayRemoteDecision point

DNSServer

RemoteDecision point

Interception points

Remote Decision Point

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Telco Overlay – PSTN Intelligent Network

• Most widely adopted PSTN overlay architecture> Goal was to add new telephony services faster and at

lower cost > Making changes in central office and switches was too

complex and expensive• Architecture

> Trigger Points – Interception & local decision points> Service Control Point (SCP) – Remote decision point

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Session Control Overlay - SIP

InternetBackbone

DNS

SIPProxy

SIP routing overlay

In-network Interception & local decision point

Remote Decision Point

SIPApp Server

ApplicationOverlay

SIPProxy

SIPProxy

Interception & local decision point

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QoS Overlay – Caching System

DNS

Origin Server

Caching Server

DNSProxy

Internet

CachingManager

QoS Monitoring

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5

4

3

2

Caching Control Overlay

Remote decision point –Application-level routing

Interception point

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DNS

Internet

Load-balancing Overlay – wide-area & local

Data Center B

DNSProxy

Wide & local area load-balancer

QoS Monitoring

Load-balancing Overlay

Remote decision point –Application-level routing

LoadBalancer

Data Center A

Data CenterNetwork

Interception &Decision point

Interception point

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QoS Routing Overlay – Best wide-area path selection

Pathentry point

switch

DNS

DNSProxy

QoS Monitoring

QoS Routing

QoS Routing Overlay

Data Center

Data CenterNetwork

On-demand connection

Backbone ISP 2

Backbone ISP 1

Traffic Manager

Interception &Decision points

Remote decision point –Application-level routing

Access ISP

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Systems requirements for Overlay network patterns• Interception and local decision points

> Based on commercial off-the shelf COTS systems with multi-threaded architecture – exploiting parallelism in packet processing

> Packet classification (deep packet inspection) – sophisticated rule-based system – beyond header fields, capable of handling application-level strings> Via packet processing engines – e.g. on top of bare HW (Netra

Data Plane Suite) or new OS functions (Solaris Crossbow)> New APIs manage packet classification rules

• Remote decision points – COTS-based > APIs with interception and local decision points

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Conclusions & Outlook• Wide range of overlay architectures can be designed with

basic patterns – Simplified approach for design of QoS overlays

• Market for QoS solutions influencing networking trends> Increased use of application-driven routing - Separation from

switching fabric> Increased centralization of routing and other transport control

functions> Increased centralization of performance management and

accounting> Increased use of on-demand bandwidth via connection-oriented

services